Ann Arbor, MI weather in August
Ann Arbor is warm and often humid in August, with frequent rain: highs average 82°F and nights drop to about 59°F. There are about 11 days with rain. This is the peak of the warm season in Ann Arbor. A good month for most outdoor plans.
- Normal high
- 82°F
- Normal low
- 59°F
- Wet days
- 11
- 3.5 in total
- Muggy days
- 9
- dew point 65°F+
How August changes from start to finish
| August 1 | August 31 | |
|---|---|---|
| Normal high | 83°F | 80°F |
| Normal low | 60°F | 57°F |
| Chance of a wet day | 38% | 35% |
| Sunrise / sunset | 6:27 am / 8:54 pm | 6:59 am / 8:11 pm |
| Daylight | 14.4 h | 13.2 h |
Chance of a wet day: average for the first and last 7 days of the month. Times are local clock time (Eastern Time).
A typical August day
- 6 am63°Fdew point 59°F
- 9 am72°Fdew point 62°F
- Noon78°Fdew point 62°F
- 3 pm81°Fdew point 61°F
- 6 pm78°Fdew point 61°F
- 9 pm70°Fdew point 62°F
NOAA hourly normals (local standard time) from Detroit Willow Run Airport (10 mi away); average wind 7 mph; clear or few clouds in 59% of daytime hours, mostly cloudy or overcast in 29%.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F9 of 31
- Hot dayshigh 90°F or more2 of 31
- Muggy daysdaily mean dew point 65°F or more9 of 31
- Wet daysat least 0.01 in of rain or melted snow11 of 31
- Notable rainat least 0.10 in6 of 31
- Freezing nightslow 32°F or below0 of 31
- Snow on the groundsnow depth 1 in or more0 of 31
Average days per August, counted from daily records for each year 1991-2020.
Rain in August
Normal precipitation is 3.5 in; a dry August brings about 2.8 in and a wet one about 3.9 in (25th and 75th percentiles). About 2 days bring half an inch or more, and about 1 an inch or more.
How August varies from year to year
- Warmest August, 1991-20202016: average high 86°F
- Coolest August1997: average high 76°F
- Wettest August1998: 8.6 in
- Driest August2008: 0.8 in
- Highest reading98°F (August 8, 2001)
- Lowest reading43°F (August 26, 2017)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
August compared with July and September
| July | August | September | |
|---|---|---|---|
| Normal high | 84°F | 82°F | 75°F |
| Normal low | 60°F | 59°F | 52°F |
| Wet days | 12 | 11 | 11 |
| Comfortable days | 6 | 9 | 16 |
| Daylight | 14.9 h | 13.8 h | 12.5 h |
Highs change by -2°F from July and -7°F into September.
Nearby alternatives in August
- Drier: Carmel, IN201 mi · high 82°F · 7 wet days
How Ann Arbor ranks in August
- Normal high284th warmest of 378 cities; 2nd of 8 in Michigan
- Wet days311th driest of 378
- Comfortable days81st most of 341
What to pack for Ann Arbor in August
- A rain jacket or umbrella – rain on about 11 days
Heating and cooling
August has 15 heating degree days and 178 cooling degree days (base 65°F), 3% of the year's total heating and cooling demand.
Questions
How hot is Ann Arbor in August?
The normal high is 82°F and the normal low is 59°F. From 1991 to 2020 the hottest August reading was 98°F (August 8, 2001).
Does it rain a lot in Ann Arbor in August?
About 11 days in August have at least 0.01 in of precipitation, and the normal total is 3.5 in. The wettest August in 1991-2020 was in 1998 (8.6 in); the driest was in 2008 (0.8 in).
Is August a good time to visit Ann Arbor?
August ranks 4th of 12 months on our comfort score for Ann Arbor (62 out of 100). It has about 9 comfortable days and about 2 days at 90°F or hotter. The best month is May.
Where the numbers come from
- Temperature, rain, snowfall, snow depth and frost dates: Ann Arbor U Of Mich (USC00200230), 3.7 mi ENE of the city center, 813 ft (68 ft lower than the city). NOAA normals and daily records, 1991-2020.
- Humidity and wind by hour: Detroit Willow Run Airport (USW00014853), 10 mi ESE of the city center, 777 ft (104 ft lower than the city). NOAA normals and daily records, 1991-2020.
- Cloud cover: Toledo Express Airport (USW00094830), 47 mi S of the city center, 669 ft (212 ft lower than the city). NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: Willow Run Airport (725376-14853), 11 mi ESE of the city center, 708 ft (173 ft lower than the city). Hourly observations, 1991-2020.